package com.qiudao.commonutil.util;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/**
 * Description: Mac 地址工具类
 * @author: gdc
 * @date: 2019/9/1
 * @version 1.0
 */
public class MacAddrUtils {

    private static String sRemoteAddr;
    private static int iRemotePort = 137;
    private static byte[] buffer = new byte[1024];
    private static DatagramSocket ds = null;


    public static DatagramPacket send(final byte[] bytes) throws IOException {
        DatagramPacket dp = new DatagramPacket(bytes, bytes.length, InetAddress.getByName(sRemoteAddr), iRemotePort);
        ds.send(dp);
        return dp;
    }

    public static DatagramPacket receive() throws Exception {
        DatagramPacket dp = new DatagramPacket(buffer, buffer.length);
        ds.setSoTimeout(2000);
        ds.receive(dp);
        return dp;
    }

    public static byte[] GetQueryCmd() throws Exception {
        byte[] t_ns = new byte[50];
        t_ns[0] = 0x00;
        t_ns[1] = 0x00;
        t_ns[2] = 0x00;
        t_ns[3] = 0x10;
        t_ns[4] = 0x00;
        t_ns[5] = 0x01;
        t_ns[6] = 0x00;
        t_ns[7] = 0x00;
        t_ns[8] = 0x00;
        t_ns[9] = 0x00;
        t_ns[10] = 0x00;
        t_ns[11] = 0x00;
        t_ns[12] = 0x20;
        t_ns[13] = 0x43;
        t_ns[14] = 0x4B;

        for (int i = 15; i < 45; i++) {
            t_ns[i] = 0x41;
        }
        t_ns[45] = 0x00;
        t_ns[46] = 0x00;
        t_ns[47] = 0x21;
        t_ns[48] = 0x00;
        t_ns[49] = 0x01;
        return t_ns;
    }

    public static String GetMacAddr(byte[] brevdata) throws Exception {
        // 获取计算机名
        int i = brevdata[56] * 18 + 56;
        String sAddr = "";
        StringBuffer sb = new StringBuffer(17);
        // 先从第56字节位置，读出Number Of Names（NetBIOS名字的个数，其中每个NetBIOS Names Info部分占18个字节）
        // 然后可计算出“Unit ID”字段的位置＝56＋Number Of Names×18，最后从该位置起连续读取6个字节，就是目的主机的MAC地址。
        for (int j = 1; j < 7; j++) {
            sAddr = Integer.toHexString(0xFF & brevdata[i + j]);
            if (sAddr.length() < 2) {
                sb.append(0);
            }
            sb.append(sAddr.toUpperCase());
            if (j < 6) {
                sb.append(':');
            }
        }
        return sb.toString();
    }

    public static void close() throws Exception {
        ds.close();
    }

    public static String GetRemoteMacAddr(String strAddr) {
        String smac = "";
        try {
            sRemoteAddr = strAddr;
            ds = new DatagramSocket();

            byte[] bqcmd = GetQueryCmd();
            send(bqcmd);
            DatagramPacket dp = receive();
            smac = GetMacAddr(dp.getData());
            close();
        } catch (Exception e) {}
        return smac;
    }
}
